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Axel van de Walle, Assistant Professor of Materials Science, has developed a general formalism to represent structure-property relationships in crystals. It enables the prediction, from a database of quantum mechanical calculations, of anisotropic material properties such as elasticity, piezoelectricity, dielectric constants, etc. As an application, he developed predictive models of anisotropic properties relevant to the design and optimization of III–V semiconductor epitaxial optoelectronic devices. This work was recently highlighted as the cover feature of Nature Materials. [Nature Article] [Commentary]

Studies of the brains of blind persons whose sight was partially restored later in life have produced a compelling example of the brain's ability to adapt to new circumstances and rewire and reconfigure itself. The research, conducted by postdoctoral researcher Melissa Saenz along with Christof Koch, the Lois and Victor Troendle Professor of Cognitive and Behavioral Biology and professor of computation and neural systems, and their colleagues, shows that the part of the brain that processes visual information in normal individuals can be co-opted to respond to both visual and auditory information. [Caltech Press Release]

Agustin J. Colussi, senior research associate in environmental science and engineering, and colleagues have found that airborne particulates impair the lungs' naturaldefenses against ozone. Their research focused on what happens when air meets the thin layer of antioxidant-rich fluid that covers our lungs, protecting them from ozone, an air pollutant that pervades major cities. "We found new chemistry at the interfaces separating gases from liquids using a technique that continuously monitors the composition of these interfaces," Colussi says. Under normal physiological conditions, ascorbic acid instantly scavenges ozone, generating innocuous byproducts. However, the researchers discovered that when the fluid is acidic, a pathological condition found in asthmatics, ascorbic acid instead reacts with ozone to form potentially harmful compounds called ozonides.

Michael Dickinson, Esther M. and Abe M. Zarem Professor of Bioengineering, is among the 190 new Fellows elected to the American Academy of Arts and Sciences this year. Dickinson studies animal physiology and behavior and has become well known for Robofly, a mechanical fly that sprang from his work on the neurobiology and biomechanics of fly locomotion. Throughout his career, Dickinson has used a variety of tools, such as wind tunnels, virtual reality simulators, high-speed video, and giant robotic models, to determine how the poppy seed-sized brains of these tiny insects can rapidly control aerodynamic forces. More than a simple understanding of the material basis for insect flight, Dickinson's studies provide insight into complex systems operating on biological and physical principles: neuronal signaling within brains, the dynamics of unsteady fluid flow, the structural mechanics of composite materials, and the behavior of nonlinear systems are all linked when a fly takes wing. [Caltech Press Release].

Using computer models of neuronal circuits and experiments on live rats, Athanassios Siapas, Assistant Professor of Computation and Neural Systems, and his postdoctoral researcher Evgueniy Lubenov are revealing the curious mechanism by which the brain spontaneously tips itself toward a state balanced between order and chaos. The driving factor in the brain's self-regulation, they say, is the timing of neural pulses. "Networks self-organize to an intermediate state, in between the two extremes," Siapas says.

"If you make structures that are impeccably designed, they also often tend to work really well," says Michael Roukes, Professor of Physics, Applied Physics, and Bioengineering. He along with senior research associate in computation and neural systems and computer science Paul Rothemund are scientists who can now add artist to their resumes. Rothemund's DNA origami and a colorized electron micrograph of Roukes's nanoscience work were displayed in Design and the Elastic Mind at the Museum of Modern Art (MoMA) in New York. Roukes's micrograph was even selected for the museum's permanent collection. [Caltech Press Release]

David Boyd, Lecturer in Mechanical Engineering, graduate student James Adleman, Demitri Psaltis, Thomas G. Myers Professor of Electrical Engineering, and David Goodwin, Professor of Mechanical Engineering and Applied Physics, have crafted the world's tiniest still to concentrate scant amounts of micromolecules for easier detection. This device may help to overcome difficulties in tracking extremely low-abundance molecular biomarkers, which can indicate disease. [Caltech Press Release]

After 16 days in space and 250 orbits of Earth, space shuttle Endeavour touched down at 8:39 p.m. EDT on Wednesday, March 26, at NASA's Kennedy Space Center. According to NASA managers, the crew members, including Caltech alumnus Robert Behnken (MS '93, PhD '97), "are in excellent shape after a safe and successful landing".